iPad Air 2

None of the keyboards that attach directly to iPad (without a cable) are supported.

However, this one works!

https://www.apple.com/shop/product/MQ052LL/A/magic-keyboard-with-numeric-keypad-us-english-silver

You can go with the Logitech Keys-to-Go Ultra Slim Keyboard since it is compatible with iPad air 2. Here is the link

You can browse through these choices as well if you want to have more options: https://www.apple.com/shop/accessories/all-accessories/mice-keyboards?page=1&f=ipad6gen&fh=40a2%2B43dd

Brydge is another high quality brand and here is their keyboard for iPad Air 2: https://www.brydge.com/products/brydge-9-7-apple-ipad-keyboard